1. Field of the Invention
The present invention relates to an antenna having patch arrays, and more particularly to an antenna having patch arrays integrally formed with a network thereof.
2. Description of Related Art
With the fast development of the wireless communication, the demands for various antennas with different properties or features are increasing. The conventional microstrip antenna is formed by mounting thin metallic patches on a substrate with a ground plate on an opposite side thereof, usually using a feed network cable or a coaxial probe to feed signals. The above metallic patches are usually thin foils with regular shapes, which maybe in shapes of a rectangle, a circle or an ellipse etc. The microstrip antenna can also utilize the metallic patches to form an array structure according to a certain regular arrangement. The pattern of a single metallic patch is difficult to control, and the gain is not high. Therefore array style is used to meet the required conditions. The technique principles of antennas are well known to the industry, so they are not described here any more.
At the present market, the microstrip antenna generally comprises a ground plate, an SIMO (single in multiple out) feed network and at least a pair of metallic patches. The feed network may be composed of multiple paths with different lengths being connected electrically with the metallic patches respectively along different transmitting directions. When electromagnetic signals are input from a signal recourse, the electromagnetic signals will be feed to each of the metallic patches through the feed network. Since the paths of the feed network have different lengths and transmitting directions, it would result in phase differences and also produce interference. The signals can be radiated out to achieve the objects and effects needed by the antenna.
Based on the fabricating and assembling techniques, the conventional array antennas may be categorized to three types.
Type A: The feed network and the metallic patches are individually manufactured and then respectively mounted on the opposite surfaces of the ground plate.
Type B: The feed network and the metallic patches are individually manufactured, mounted on the same surface of the ground plate and located at different altitudes.
Type C: The metallic patches and the feed network in the form of microstrip cable are individually manufactured and integrated on a PCB.
Since the feed network and the metallic patches are individually produced, assembling them to the ground plate respectively would result in higher complexity and obvious interference. Further, the foregoing type C also makes the microstrip increases partial loss, and deteriorates the radiation properties including the gain and the sidelobe level.
With reference to U.S. Pat. No. 6,326,920, Barnett discloses an antenna comprising a ground plate, a feed network and multiple metallic patches in pairs integrally connected to the feed network. However, the flat configuration of each metallic patch may cause the sidelobe and energy dissipation problem.